I bought a MeLE quiet PC (little bigger than a pi but with case, x86, ssd, 16gb memory) and installed OpenSUSE Tumbleweed because I wanted a rolling distro. Installed kodi, mounted it on the back of a large monitor. Using a cheap Startech 7.1 USB audio on a long USB connection that takes it all the way to the Yamaha receiver. I've attached a 2TB HDD to the MeLE and that holds most of my stuff. There's a NAS in the attic too.
For the pipewire / pulseaudio channel mapping I can go into the boring details if you want
Thanks for the extra detail. I have been wanting to build a dedicated Jellyfin client for a TV for a while to avoid any 'Smart' TV festures. Does your system boot directly into Kodi? I have been wanting to build something similar for a Jellyfin player. Did you set up an IR remote as well?
Well, it boots to a KDE Plasma desktop that launches Kodi (full screen). It also starts MusicBee (windows app that runs perfectly in wine, with a few tricks). I had tried jellyfin but ditched it back when my SBC was a Raspberry pi 4. Because that sucked so much that I abandoned it, attached a large drive and used Kodi instead (ie: I don't stream, I play locally attached content). It's easy to set up a DLNA listener too, so I can fling music or movies to gmedia-resurrect. It's constantly listening in the background, and plays whatever I send to it (eg: from bubble upnp)
Oh, and I plug a Logitech Bluetooth audio receiver into the line-in on the USB 7.1 soundcard, so I can pay music from a phone or my HiBy R2 DAP.
About the Pi: it sucked for a heap of reasons. I found myself fighting stupid battles over and over. Switching to an x86 made all of those problems disappear immediately. Stay the hell away from the Pi, is my advice.
I don't have a remote actually, I use the Kodi Android remote, MusicBee Android remote and kdeconnect (for everything else).
For the pipewire / pulseaudio channel mapping I can go into the boring details if you want